A FFT based algorithm for the formation of wide-angle ISAR images using EIP

This paper describes a new algorithm for implementing wide angle imaging. The new algorithm is derived from the enhanced image processing (EIP) algorithm described by Ausherman et al. (1984) and is based on using the Fast Fourier Transform (FFT) to rotate and interpolate the linear images before compositing. The new algorithm is more accurate than the linear interpolation based compositing scheme used by Ausherman and is designed to perform efficiently on modern vector array processors. First, correlation imaging and the relationship between linear imaging and wide angle imaging is discussed. Following the discussion of the enhanced imaging technique, the new algorithm for implementing the EIP is described. After the theory is discussed, an example demonstrating the efficacy of the new algorithm is presented. The effect of different strategies for reducing sidelobes in the EIP imagery is also discussed. A comparison of the computational complexity of the new algorithm with the traditional algorithm is presented. The paper concludes with a summary.